Error accessing application id tfs from secure store service

Hi all,
I have been doing this just recently and having a hard time checking on what might be wrong. I am really going crazy about this kind of problem that others might have been experiencing too. I am using a dual sever setup, the TFS 2010 and SharePoint 2010. I got this kind of error saying
“Excel
An error occurred while accessing
application id tfs from Secure Store Services.
The following connections failed to
refresh:
TfsOlapReport
Learn more about data refresh”
Every time I go for one of the reports to the dashboard page in SharePoint. I tried reloading and refreshing the page, but the same error appears on my screen. Then if I click a report on the excel reports on the SharePoint portal, I also get the same error. I tried clicking ok to the error message and a report showed up, but do not contain any data. So can anyone find a solution to this kind of problem?
Thanks!
